Entomopathogenicity of fungi in combination with Ricinus communis extract for the control of Aleurocanthus woglumi

Abstract

AbstractCitrus is among the most important crops in the world, and has suffered losses of up to 80% due to the citrus blackfly, Aleurocanthus woglumi Ashby (Hemiptera: Aleyrodidae). The combined use of entomopathogenic fungi and plant extracts is a sustainable alternative to control this pest. The objectives of this study were to select entomopathogenic fungi to control A. woglumi and verify the insecticidal effect of the combined use of the selected fungi and aqueous extracts of castor bean leaves, Ricinus communis L. (Euphorbiaceae). Twenty fungal isolates obtained from field‐collected dead A. woglumi were identified and tested against the insect. Eight were identified as belonging to Fusarium incarnatum‐equiseti species complex, nine to Fusarium fujikuroi species complex, two to Cordyceps javanica (Bally) Kepler, B. Shrestha & Spatafora, and one to genus Akanthomyces. The five isolates that caused the maximum confirmed mortality were tested for compatibility with aqueous castor bean extract at 5, 10, and 20% (wt/vol) concentrations. Qualitative phytochemical analysis showed the presence of alkaloids, glycoside flavonoids, saponins, and tannins in the castor bean extract. Most of the isolates studied caused high confirmed mortality of citrus blackfly. In the compatibility tests, Fusarium volatile Al‐Hatmi, Sand.‐Den., SA Ahmed & de Hoog and Fusarium proliferatum (Matsush.) Nirenberg ex Gerlach & Nirenberg combined with the 5% aqueous extract were the most suitable for testing against A. woglumi. Additive interactions were observed for the combined control agents. The highest value of confirmed mortality (98.2%) was observed for the combination of 5% aqueous castor bean extract and F. volatile (URM 8051), the efficacy of which should be confirmed by field tests.